APOD: Arp 188 and the Tadpole's Tail (2014 Aug 25)

[APOD Robot]

Arp 188 and the Tadpole's Tail

Explanation: Why does this galaxy have such a long tail? In this stunning vista, based on image data from the Hubble Legacy Archive, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation Draco. Its eye-catching tail is about 280 thousand light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 - from right to left in this view - and was slung around behind the Tadpole by their gravitational attraction. During the close encounter, tidal forces drew out the spiral galaxy's stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper right. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail's star clusters forming smaller satellites of the large spiral galaxy.

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[Mactavish]

The galaxy appears to have at least two (or more) spiral arms. Why has only one seem to have been drawn out by the tidal forces and not the others as well? Any explanations or theories? (This is the best image yet of Arp 188. Great job of processing.)

[Bobarino]

Great image. I could only imagine living on that arm just outside the main galactic disk. What a view in the evening sky

[Ann]

I love this image! Arp 188 is a fantastic galaxy, and the processing of the image is really great!

Ann

[antony]

The description tells us that Tadpole's "tail" is destined to become satellite galaxies of the main galaxy. Might the same process be the origin of the Large and Small Magellanic Clouds?

[Boomer12k]

Awesome.

And it looks like the one farther back is doing the same....

:---[===] *

[starsurfer]

The description tells us that Tadpole's "tail" is destined to become satellite galaxies of the main galaxy. Might the same process be the origin of the Large and Small Magellanic Clouds?

There is a theory that the Magellanic Clouds were simply captured by the Milky Way in the past. I think they are quite large to have developed out of tidal dwarf galaxies forming in a tidal tail.

[starsurfer]

Also I prefer the original version, this reprocessing loses the brightness dynamic range. I wonder if any Ha images have been taken of the tidal tail? They are also likely to include planetary nebulae!

[Chris Peterson]

Also I prefer the original version, this reprocessing loses the brightness dynamic range. I wonder if any Ha images have been taken of the tidal tail? They are also likely to include planetary nebulae!

It's about intent. The current image is (I think) very unaesthetic, for precisely the reason you suggest. But this kind of treatment is necessary when the intent is to demonstrate the relative structure of different parts. There's really no way to present something that simultaneously shows structure and relative brightness. This object simply covers too many decades of intensity.

[beekayjohn]

This photo is opposite from one I saw years ago on this same site, meaning the tail runs off to the right instead of the left. Which image is the correct perspective? One or the other has been flipped, methinks!
Bee

[Chris Peterson]

This photo is opposite from one I saw years ago on this same site, meaning the tail runs off to the right instead of the left. Which image is the correct perspective? One or the other has been flipped, methinks!
Bee

What is "correct"? What is "flipped"?

There is a convention commonly used by astroimagers, both professional and amateur, to display images with north up, east left. But that's all it is, a convention, and one that's commonly not observed, either because the shape of the object and sensor don't allow it, or for aesthetic reasons. Today's image is roughly north to the upper left, east to the lower left, which is no more "correct" than any other chosen rotation. If you were observing this visually, or through a telescope, its apparent rotation angle would depend simply on the direction you were facing on the ground.

[FloridaMike]

... decades of intensity.

Hey Chris,

Can you elaborate on what you mean by this phrase?

[Chris Peterson]

... decades of intensity.

Hey Chris,

Can you elaborate on what you mean by this phrase?

"Decades" = "orders of magnitude" = "factors of ten".

[LocalColor]

Wonderful image - so many galaxies! (Hard to pinpoint the "intruder".)

[Ron-Astro Pharmacist]

I too find it fascinating that there are only six stars in this field. There are a lot of galaxies showing.

You can sense the three dimensional structure of this collision but it isn't completely obvious. Too bad that much of astrophotography isn't amenable to using the red-blue concept though I doubt I understand it well enough to be even commenting on it. Maybe one day we will be able to have two space telescopes far enough apart to produce dual images capable of producing an anaglyph. I suspect those would have to be some wide-set eyes. I don't suppose an orbit-wide parallax-type trick would work – even on something much closer? Please laugh if you can tell I don't have much of a sense for the distances and concepts involved.

[geckzilla]

I too find it fascinating that there are only six stars in this field. There are a lot of galaxies showing.

There are probably many more than six Milky Way stars in the field. One thing I have learned is that very local faint stars can easily become confused with background objects as they approach similar brightness to the brightest groups of stars from distant galaxies.

Example:


This image flickers back and forth between two different epochs. Same filter, iirc. Years apart. I have been suspicious of these very tiny dots being faint components of our galaxy but until I found this fine, accidental parallax shift in Hubble's archive, I wasn't sure.

[starsurfer]

I too find it fascinating that there are only six stars in this field. There are a lot of galaxies showing.

There are probably many more than six Milky Way stars in the field. One thing I have learned is that very local faint stars can easily become confused with background objects as they approach similar brightness to the brightest groups of stars from distant galaxies.

Example:


This image flickers back and forth between two different epochs. Same filter, iirc. Years apart. I have been suspicious of these very tiny dots being faint components of our galaxy but until I found this fine, accidental parallax shift in Hubble's archive, I wasn't sure.

You never cease to amaze me!

[Ann]

Indeed, that's extremely well spotted, Geck!

Ann

[DavidLeodis]

I would be grateful if someone could please point out for me where the intruder galaxy is. The explanation would seem to imply it should be obvious, but I don't know where exactly it is "seen through foreground spiral arms at the upper right".

Edit added later. I've now found that Arp 188 was the topic of the APOD of November 8 2012 and in a discussion of that APOD a link was provided to information that showed where the intruder galaxy is in Arp 188. This is the link:- http://hubblesite.org/gallery/tours/tour-tadpole/. To find the image needs some patience. Click on the 'Click to play movie' then wait a bit then click on the 'Distorted shape' section and working through that will bring up an annotated image in which the position of the intruder galaxy is labelled. I hope that all makes sense!

[Roland]

This photo is opposite from one I saw years ago on this same site, meaning the tail runs off to the right instead of the left. Which image is the correct perspective? One or the other has been flipped, methinks!
Bee

What is "correct"? What is "flipped"?

There is a convention commonly used by astroimagers, both professional and amateur, to display images with north up, east left. But that's all it is, a convention, and one that's commonly not observed, either because the shape of the object and sensor don't allow it, or for aesthetic reasons. Today's image is roughly north to the upper left, east to the lower left, which is no more "correct" than any other chosen rotation. If you were observing this visually, or through a telescope, its apparent rotation angle would depend simply on the direction you were facing on the ground.

Beekayjohn is correct this image is flipped from the previous showing on 8 Nov 2012. I don't mean rotated image I mean mirror image rotated. This image is the same as all of the ones before the last one, although some of the images are rotated. This is the sixth showing I found on this site. It is definitely one of my favorites.